Changes of prostate gland volume with and without androgen deprivation after intensity modulated radiotherapy - A follow-up study.
OBJECTIVE
The shrinking effect of androgen deprivation therapy (ADT) on prostate volume is a known finding, but data on volume changes during radiotherapy are inconsistent. We examined patients with and without ADT undergoing intensity modulated radiotherapy (IMRT) and performed follow-up examinations to study volume changes before and after radiotherapy.


METHODS
Prostate volumes between planning magnetic resonance imaging (MRI) and last available follow-up MRI were retrospectively determined in 39 patients. Median time interval between first and last MRI was 233days (range 126-813). Two observers performed volume measurements in consensus and were blind to the timing of MRI. Volume changes over MRI were determined using the ellipsoid formula. Data of patients with and without ADT were compared by a linear mixed model.


RESULTS
Of 39 patients, 22 had ADT with a median duration of 5months (range 1-24). ADT patients showed lower prostate volume throughout the study period (-28% to 38%). Although individual shrinking effect was highly variable, patients treated with IMRT but without ADT showed a significantly larger volume reduction (26.1%) than patients with ADT (12.9%, p<0.05).


CONCLUSIONS
Patients undergoing IMRT show definite prostate shrinkage. The rate is slowed down after 6months in both groups, whereas the volume reduction is significantly larger in patients without ADT. Nevertheless there is no adding effect of ADT+IMRT vs. IMRT alone.
Zechmann
Christian M
CM
Department of Radiology, German Cancer Research Center, Heidelberg, Germany. c.zechmann@dkfz.de
Aftab
Khurram
K
Didinger
Bernd
B
Giesel
Frederik L
FL
Zamecnik
Patrik
P
Thieke
Christian
C
Fütterer
Jurgen J
JJ
Kopp-Schneider
Annette
A
Kauczor
Hans-Ulrich
HU
Delorme
Stefan
S
D000726:Androgen Antagonists / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D011467:Prostate / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*
D000726:Androgen Antagonists